Crown Prince Haakon celebrated his 35th year birthday at his and Crown Princess Mette-Marit's new summerhouse at Flatholmen, just outside Ris┐r in Norway.Mette-Marit's mother Marit Tjessem left with Princess Ingrid Alexandra and Prince Sverre-Magnus after she had eaten lunch with them at the summerhouse.She was going to babysit them while Crown Prince Haakon and Crown Princess Mette-Marit was celebrating his birthday with 13 of there close friends:All Over Press FinlandAll Over Press FinlandAll Over Press FinlandAll Over Press FinlandAll Over Press Finland